Abstract Detail

Reproductive biology of Hydrocharis morsus-ranae in Lake Champlain, a likely source population for the next region-wide aquatic plant invasion.

Hydrocharis morsus-ranae L. (European frogbit, Hydrocharitaceae) is an invasive aquatic plant species first introduced to North America in 1932. The species spreads rapidly by the production and growth of stolons, which enable growth through clonal reproduction, and turions (overwintering buds) that allow the populations to reestablish themselves each spring. The primary focus of this study is to explore the reproductive biology of H. morsus-ranae in Lake Champlain, where it has become established relatively recently. Field surveys were conducted in three different sites on the western shore of Lake Champlain: Point Au Roche State Park, Ausable Point Wetland Management Area, and the mouth of the Little Chazy River, all located within 20 miles of Plattsburgh, NY. This work evaluates the potential of the local infestation to adapt and evolve through sexual reproduction. Wild populations were surveyed for breeding system and gender status (dioecious/male, dioecious/female, or monoecious) and natural fruit/seed set. Individual pre-flowering plants from each population were harvested in late spring and transferred to water tanks in the greenhouse on the SUNY Plattsburgh campus, where a series of hand pollination tests were performed. The results are used to determine whether Lake Champlain populations are capable of sexual reproduction (evidenced by fruit/seed set) in addition to asexual (clonal) methods. Our findings are important in determining the reproductive status of an existing population of aquatic invasive plants that is likely to be the source of a much larger invasion. The hope is that the data gathered in this study will be used for early detection and rapid response plans for “downstream” areas that have not yet been invaded but are likely to be so in the future.